Approximately 10 million people in the United States have hypothyroidism including an estimated 10 percent of all American women. This condition can have widespread consequences throughout the body. There are a variety of diseases and conditions that can cause hypothyroidism.

What is hypothyroidism?

Hypothyroidism is a condition where the thyroid gland does not produce enough thyroid hormone. The thyroid gland is located in the front part of the neck below the voice box (larynx). The thyroid produces thyroid hormone which is a chemical messenger used by the brain to control metabolism.

Metabolism is the combination of all the processes in the body that convert or use energy, including breathing, blood circulation, temperature, digestion, muscle movement, and brain function. Thyroid hormone also affects growth and development.

The amount of thyroid hormone produced by the body is regulated by other glands called the pituitary gland and the hypothalamus. These two glands detect chemicals in the blood and release their own hormones to trigger the thyroid to release more or less thyroid hormone.

What causes hypothyroidism?

Some common causes of hypothyroidism include:

• Thyroid inflammation – swelling in the thyroid can damage the cells in the gland that produce thyroid hormone. This may be the result of an autoimmune condition attacking the thyroid gland.

• Pregnancy – Some women develop hypothyroidism after giving birth.

• Birth defects

• Radiation treatments – Radioactive iodine used to treat overactive thyroid or radiation to treat cancer of the neck or brain can damage the thyroid.

• Surgery to remove part of the thyroid due to other thyroid problems.

• Certain medications

Hypothyroidism is more likely to occur in women than in men and is more common after age 50. The condition can usually be diagnosed through a blood test, although some people require more extensive testing. If you have questions or concerns about hypothyroidism, talk to your health care provider.

Sources:

Medline Plus. Hypothyroidism. Web. December 4, 2011.
http://www.nlm.nih.gov/medlineplus/ency/article/000353.htm

PubMed Health. Hypothyroidism. Web. December 4, 2011.
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001393/

Endocrine Web. Hypothyroidism: Too Little Thyroid Hormone. James Norman, MD, FACS, FACE. Web. December 4, 2011.
http://www.endocrineweb.com/conditions/thyroid/hypothyroidism-too-little-thyroid-hormone

Medicine Net. Hypothyroidism. Ruchi Mathur, MD, FRCP(C). Web. December 4, 2011.
http://www.medicinenet.com/hypothyroidism/article.htm

Medline Plus. Metabolism. Web. December 4, 2011.
http://www.nlm.nih.gov/medlineplus/ency/article/002257.htm

Reviewed December 6, 2011
by Michele Blacksberg RN
Edited by Jody Smith